Influence of different energy patterns on efficacy of radial shock wave therapy

One of the mechanisms of the efficacy of extracorporeal shock wave therapy (ESWT) for impaired muscle coordination of limbs is the destruction of Acetylcholine receptors (AChRs) at neuromuscular junction. The highly increased density of AChRs can change the acoustic impedance, and this change of the acoustic impedance can be the reason that radial shock wave (rESW) destroy AChRs selectively. However, the relationship between applied energy of rESWs and the therapeutic efficacy remains unclear, although some studies compared the clinical efficacy of rESWT between high- and low-energy applications. This study aimed to compare the CMAP change among different energy and pulses of rESW application.

Male Sprauger-Dawley rats were used. A device that generates radial shock waves pneumatically, was used to apply the following six patterns of radial extracorporeal shockwaves in different energy flux densities and pulses to the right calf of each rat: 1, 8000 pulses at 0.045 mJ/mm²; 2, 4000 pulses at 0.09 mJ/mm²; 3, 2000 pulses at 0.18 mJ/mm²; 4, 4000 pulses at 0.045 mJ/mm²; 5, 2000 pulses at 0.09 mJ/mm²; 6, 1000 pulses at 0.18 mJ/mm². Left calf muscles were considered controls.

There was a significant reduction in CMAP amplitude between control and rESW-exposed muscles in the group applied 4000 pulses with EFD at 0.09 mJ/mm² and the group applied 2000 pulses with EFD at 0.18 mJ/mm². However, the group applied 8000 pulses with EFD at 0.045 mJ/mm² and all groups which was exposed to total 180 mJ rESW application did not show a significantly decreased CMAP amplitude compared with the untreated side.

Total energy and energy flux density correlate with a decrease in CMAP amplitude by rESW application. These findings could be availed by clinicians in actual clinical setting for the proper application of rESW.